This invention relates to data processing systems, and more particularly to a real time digital data analyzer for display and compression of laser velocimeter derived frequency burst signal data.
The application of the laser velocimeter as a nonperturbing fluid-flow velocity measuring tool has been discussed in the literature. It has been shown that two mutually coherent and like polarized laser beams when crossed, establish planar interference fringes in the crossover region. Light scattering centers passing through the crossbeam region provide frequency burst type signals when viewed by a photodetecting device. These frequency burst signals may be digitized and can provide data sampling rates that may exceed 100,000 samples per second. Data typically exists in 16 bit binary or 20 bit BCD word form. Existing digital data acquisition systems are presently limited to a nominal 10,000 word continuous acquisition rate. The present invention permits a 10 to 1 increase in the word acquisition rate and provides data compression and an on-line visual display of the acquired data in histogram form. The grouped data may subsequently be processed to yield such statistical quantities as the mean, standard deviation, mode, skewness, kurtosis and maximum-minimum values of the data.